Her crime: On the fringes of the annual state-sponsored demonstration honoring old-school communists Rosa Luxembourg and Karl Liebknecht, Ms. Lengsfeld and friends carried a banner bearing a quote from Luxembourg: "Freedom is Always the Freedom to Dissent."

As it turned out, Lengsfeld returned to Berlin on Nov. 9, 1989, the day the Berlin Wall fell, and was elected to parliament first for the left-wing Greens and then the conservative Christian Democrats.

But as German voters head to the polls this Sunday to elect state legislatures in Hesse and Lower Saxony, Lengsfeld is troubled by the polls. The rag-tag band of surviving members of former East Germany's ruling communist party could emerge as a formidable, possibly decisive force. The party, now simply called The Left after merging last year with an alliance of west German leftists, has regrouped to become the third-largest political force in unified Germany. A year before the campaign for the next national elections gets under way in 2009, these provincial state polls will be a test of power for Germany's new left – and set the country's political agenda.

Lengsfeld is filled with anger. "It's just absurd," she says. "We thought they were so discredited that no one would ever vote for them again."

According to the respected Allensbach polling agency, The Left are now the third most-popular party behind the Christian Democrats (CDU) and the Social Democrats (SPD). In its December poll, 37.9 percent of those surveyed said that if national elections were held now, they would vote for the CDU, compared with 28 percent for the SPD and 10.6 percent for The Left. That puts The Left ahead of Germany's pro-business liberal Free Democrats, who polled 10.4 percent, and the environmentalist Greens, with 9.5 percent.

Not only are large numbers of Germans prepared to vote for The Left, but opinion polls consistently show that many voters believe the former communists are more likely to confront the injustices they feel have come with globalization – the gap between rich and poor, for example, and standing up for a strong social welfare state.

These used to be the core themes that won elections for the SPD. But as leader of the government from 1998 to 2005, the SPD pushed through economic reforms, cut taxes, and refused to bend to the unions. And now, according to Allensbach, 29 percent of those polled say The Left is more likely to defend the social welfare state, compared with 22 percent who chose the SPD. A whopping 44 percent said The Left is more likely to narrow the gap between rich and poor, compared with just nine percent for the SPD.

The Left has made Hesse, which is home to Frankfurt, Germany's financial capital, their proving ground. Pollsters say the party is likely to get 5 percent of the vote, the threshold it needs to cross to gain representation in the state legislature. Gregor Gysi, a former East German lawyer and one of the main architects of the party's resurgence, has made clear that victory in Hesse is just a stepping stone on the road to Berlin.

"It would mean a cultural shift in this country," Mr. Gysi told reporters in Wiesbaden while out on the campaign trail. "If we make it into parliament in one or more western states, that means people are saying they want a political culture that is further to the left than the SPD."

Hesse is also a political laboratory for the SPD. The key candidates in Hesse are the same people who waged bitter campaign against the SPD's economic reforms. If the SPD wins in Hesse on a leftist ticket, then the party is likely to swing even further left.

"Facing this inner-party confrontation, [SPD party chairman Kurt] Beck is trying to take the party back to its roots," says Bernhard Wessels, a political scientist at Berlin's Free University. "They are closely watching Hesse; it will have implications for the federal election campaign."

The SPD front-runner in Hesse is Andrea Ypsilanti, the daughter of an immigrant auto worker. If elected, she has promised to work for a federal tax on the wealthy and to shut down not only the state's nuclear power plants but also its coal-fired power plants.

Her CDU rival, the incumbent governor Roland Koch, is hoping to galvanize conservative voters. He tried to make political hay out of an attack in Munich by immigrant youths on a pensioner, sparking a national debate about xenophobia. Ms. Ypsilanti and Mr. Koch are now running neck-and-neck. The problem for both of them is that if the election ends up in a dead heat, neither may be able to form a coalition that gives them a stable majority.

The thought that the former East German Communist Party could wield any power in Germany again angers the victims of the regime. A year after unification, Lengsfeld was able to read the file the Stasi secret police kept on her. In it she discovered that her husband had been a Stasi spy for years, charged with reporting on her activities.

"Nothing has changed in the party. There are a lot of new faces, but the ones who have anything to say are from the old guard," says Lengsfeld.

SPD leaders say they will never form a coalition with The Left in a western state or at the federal level. But Lengsfeld doesn't believe them. "If there is a numerical majority with The Left, and even if it's just one vote, you can bet your life on it that the SPD will jump at the chance," she says.